In ink-jet recording apparatus, ink is supplied to a recording head by connecting an ink tank to the recording head detachably or by connecting an ink tank provided outside a carrier to a recording head on a carriage via a flexible ink tube.
To maintain good performance of ink ejection from the recording head, it is necessary to keep the ink pressure in the recording head almost constant.
JP-A-62-231759 discloses a technique in which an inverted-umbrella-shaped check valve is disposed between an ink tank and a recording head which is provided under the ink tank. When ink droplets are ejected from the recording head, the check valve is opened due to a pressure reduction on the recording head side and ink is thereby supplied from the ink tank.
In tube-supply-type ink-jet recording apparatus, recording is performed as the carriage mounted with the recording head is reciprocated along a guide rod. Therefore, the force of inertia acts on the ink in the ink tube as the carriage is accelerated or decelerated, as a result of which a pressure variation occurs in ink supplied to the recording head.
One measure which is employed to solve the above problem is to absorb a pressure variation by changing the volume of a buffer room provided in part of an ink channel on the carriage by, for example, forming one side of the buffer room with a flexible film or storing air in the buffer room. JP-A-2004-268448 proposes a technique in which a communication hole is formed at the center of a movable valve. In an ordinary state, the communication hole is located at the same position as the ink channel to enable supply of ink to the recording head. While the carriage is accelerated or decelerated, the communication hole is deviated from the ink channel due to the inertia of the movable valve and the ink supply is thereby restricted.